Abstract

Lighting control system for Camera based barcode reader is a system that automatically controls the illumination of the barcode lighting device by sensing the light intensity reflected off the barcode. Automatic light sensing, comparing the intensity level and illumination control have been developed in order to reduce light reflection from the barcodes. In this project, microcontroller is used to implement the light control strategies such as turn on or off the number of LEDs automatically and thus controls the brightness of the light source. The system has been designed in such a way that, it can capture the barcodes and process them perfectly under different lighting conditions. The different lighting conditions are produced by barcodes printed on different objects such as shiny covers, plastic wraps, round shaped bottle etc. The camera lens is used to detect the light intensity and to send the correct signal to microcontroller to perform the suitable actions. Thus, it reduced the use of extra sensor circuit for light sensing. A digital to analog convertor is used to convert the binary codes into analog voltages. This voltage is supplied to the power circuit for controlling the light intensity. The microcontroller is pre-programmed to do this task efficiently. Finally, some laboratory experiments have been conducted to validate the efficiency of the control circuit.